The present invention relates the field of plugs for hydraulic ports. More particularly, the present invention relates to a port plug for hydraulic components having a SAE (Society of Automotive Engineers) straight (internal) thread o-ring boss port. The port plug of this invention is also adaptable to other types of ports.
When contaminate sensitive hydraulic components such as pumps, motors and the like are manufactured and prepared for shipment to a customer, frequently the connection ports have temporary "shipping" plugs installed. The purpose of these plugs is to seal hydraulic fluid such as oil inside the component during shipping, as well as to prevent external contaminants from entering the component. When the customer receives the hydraulic component and is preparing it for use, these temporary shipping plugs are removed and discarded so that permanent hydraulic fittings can be installed.
It is well known in the hydraulic industry to use plastic externally threaded plugs as temporary shipping plugs in hydraulic components. Various plastic materials, including, but not limited to, polyethylene, are commonly used. Such plugs are quite economical, readily available, relatively easy to use and are usually reliable. These plugs, however, have been found to occasionally present problems in use. If these externally threaded plastic plugs are not installed properly, cross-threading can result and plastic contaminants or shavings can be left in the ports of the hydraulic components when the plugs are removed. Subsequently, these plastic contaminants are ingested by the hydraulic component which can result in operational failure. Even with proper installation, some plastic shavings may be generated by the installation and removal processes and thereby contaminate the hydraulic component once the permanent hydraulic fittings are installed.
Therefore, a primary objective of the present invention is the provision of a resilient elastomeric plug that provides an effective seal for a hydraulic port and yet substantially reduces or eliminates any possible contamination resulting from the use of the plug.
A further objective of the present invention is a provision of a port plug that has an integral circumferential annular bead thereon for sealingly engaging the o-ring surface on a SAE threaded o-ring port.
A further objective of the present invention is a provision of a plug that has a smooth unthreaded outer diameter thereon for frictionally engaging the internal threads of a SAE port.
A further objective of the present invention is the provision of a plug which is simple to install and remove.
A further objective of the present invention is the provision of a plug which is economical to manufacture, as well as durable and reliable in use.
These and other objectives will be apparent from the drawings, as well as from the description and the claims which follow.